Carbon-based nanostructures, including two-dimensional graphene nanosheets and graphene-based materials, have garnered an increasingly large amount of scientific interest in recent years due to their structural and electronic properties. Conventional methods for synthesizing graphene-based materials utilize graphite oxide (GO) as a starting material, which can be prepared in bulk quantities from commercial-grade graphite under strong oxidizing conditions. GO in its bulk form is a layered material composed of a variety of oxygen-containing functionalities, for example, epoxides and tertiary alcohol groups are generally found on the basal plane and carbonyl and carboxyl groups along the sheet edges. The diversity and density of functionality in GO provides a platform for chemistry to occur both within the intersheet gallery and along sheet edges.
Despite the recent upsurge in methods for forming graphene derivatives along with subsequent incorporation of the products into graphene-based devices, only a few methods exist to covalently functionalize the basal plane of graphene. Moreover, current methodology often introduces basal plane functionalities that are weakly bound to the graphene surface through carbon-oxygen (C—O) or carbon-nitrogen (C—N) bonds and therefore, the resulting material generally cannot survive further thermal, electrochemical, and/or chemical treatment of the graphene-based material. The labile nature of such chemical functionalities represents a significant drawback to the currently available technology, as in many cases it is necessary to deoxygenate the graphene derivatives under relatively harsh conditions to reestablish electrical conductivity within the graphene nanosheet. Additionally, incorporation of these C—O or C—N modified graphene materials into devices can intrinsically limit the thermal and/or electrochemical boundaries of the device.